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National Oil and Hazardous Substances Pollution Contingency Plan; National Priorities List

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AGENCY:

Environmental Protection Agency (EPA).

ACTION:

Direct final notice of deletion of the Waverly Groundwater Contamination Superfund Site (Site) from the National Priorities List (NPL).

SUMMARY:

The EPA, Region 7, is publishing a direct final notice of deletion of the Site, located near Waverly, Nebraska, from the NPL. The NPL, promulgated pursuant to section 105 of the Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) of 1980, as amended, is Appendix B of 40 CFR part 300, which is the National Oil and Hazardous Substances Pollution Contingency Plan (NCP). This direct final deletion is being published by the EPA with the concurrence of the state of Nebraska through the Nebraska Department of Environmental Quality because the EPA has determined that responsible parties or other persons have implemented all appropriate response actions required and, therefore, no further remedial action pursuant to CERCLA are appropriate.

DATES:

This direct final deletion will be effective November 20, 2006 unless EPA receives adverse comments by October 19, 2006. If adverse comments are received, the EPA will publish a timely withdrawal of the direct final deletion in the Federal Register informing the public that the deletion will not take effect.

ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-HQ-SFUND-1986-0005, by one of the following methods:

  • http://www.regulations.gov—Follow the online instruction for submitting comments.
  • E-mail: hirter.fritz@epa.gov.
  • Fax: 913-551-9130.
  • Mail: Mr. Fritz Hirter, Community Involvement Coordinator, U.S. EPA, Region 7, 901 N 5th Street, Kansas City, Kansas 66101. Start Printed Page 54764
  • Hand Delivery: 901 N 5th Street, Kansas City, Kansas.

Such deliveries are only accepted during the Docket's normal hours of operation, and special arrangements should be made for deliveries of boxed information.

Instructions: Direct your comments to Docket ID No. EPA-HQ-SFUND-1986-0005. The EPA's policy is that all comments received will be included in the public docket without change and may be made available online at http://www.regulations.gov, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through http://www.regulations.gov or e-mail. The http://www.regulations.gov Web site is an “anonymous access” system, which means the EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to the EPA without going through http://www.regulations.gov, your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, the EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If the EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, the EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.

Docket: All documents in the docket are listed in the http://www.regulations.gov index. Although listed in the index, some information is not publicly available, e.g., CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in http://www.regulations.gov or in hard copy at the EPA's Region 7 Superfund Records Center, 901 N 5th Street, Kansas City, Kansas 66101 and the Waverly City Hall, Lancashire Street, Waverly, Nebraska 68462-1131. Region 7's Docket Facility is open from 8 a.m. to 4 p.m. by appointment, Monday through Friday, excluding legal holidays. The EPA Docket telephone number is 913-551-7166. The Waverly City Hall is open from 8 a.m. to 4 p.m., Monday through Friday, excluding legal holidays, or by appointment. The Waverly City Hall telephone number is 402-786-2312.

Information Repositories: Comprehensive information on the Site is available for viewing in the Deletion Docket at the information repositories located at: U.S. EPA, Region 7, Superfund Division Records Center, 901 North 5th Street, Kansas City, Kansas 66101; and the Waverly City Hall, Lancashire Street, Waverly, Nebraska 68462-1131.

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FOR FURTHER INFORMATION CONTACT:

Mr. Fritz Hirter, Community Involvement Coordinator (PLMG/OEP) U.S. Environmental Protection Agency, Region 7, 901 N 5th Street, Kansas City, Kansas 66101, telephone number: 1-800-223-0425 or (913) 551-7130; fax number: 913-551-9130; e-mail address: hirter.fritz@epa.gov.

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SUPPLEMENTARY INFORMATION:

Table of Contents

I. Introduction

II. NPL Deletion Criteria

III. Deletion Procedures

IV. Basis for Intended Site Deletion

V. Applicable Deletion Criteria

I. Introduction

The EPA, Region 7, is publishing this direct final notice of deletion of the Waverly Groundwater Contamination Superfund Site (Site) from the National Priorities List (NPL).

The EPA identifies sites that appear to present a significant risk to public health or the environment and maintains the NPL as the list of those sites. As described in § 300.425(e)(3) of the NCP, sites deleted from the NPL remain eligible for remedial actions if conditions at a deleted Site warrant such action.

Because the EPA considers this action to be noncontroversial and routine, the EPA is taking it without prior publication of a notice of intent to delete. This action will be effective November 20, 2006 unless the EPA receives adverse comments by October 19, 2006 on this document. If adverse comments are received within the 30-day public comment period on this document, the EPA will publish a timely withdrawal of this direct final deletion before the effective date of the deletion and the deletion will not take effect. The EPA will, as appropriate, prepare a response to comments and continue with the deletion process on the basis of the notice of intent to delete and the comments already received. There will be no additional opportunity to comment. Section II of this document explains the criteria for deleting sites from the NPL. Section III discusses procedures that EPA is using for this action. Section IV discusses the Site and demonstrates how it meets the deletion criteria. Section V states the EPA's action to delete the Site from the NPL unless adverse comments are received during the comment period.

II. NPL Deletion Criteria

Section 300.425(e) of the NCP provides that releases may be deleted from the NPL where no further response is appropriate. In making a determination to delete a Site from the NPL, the EPA shall consider, in consultation with the state, whether any of the following criteria have been met:

a. Responsible parties or other persons have implemented all appropriate response actions required.

b. All appropriate responses under CERCLA have been implemented, and no further response action by responsible parties is appropriate.

c. The remedial investigation has shown that the release poses no significant threat to public health or the environment and, therefore, the taking of remedial measures are not appropriate.

Even if a site is deleted from the NPL, where hazardous substances, pollutants, or contaminants remain at the deleted site above levels that allow for unlimited use and unrestricted exposure, CERCLA Section 121(c), 42 U.S.C. 9621(c) requires a subsequent review of the site to ensure that the remedy remains protective of public health and the environment. If new information becomes available which indicates a need for further action, the EPA may initiate remedial actions. Whenever there is a significant release from a site deleted from the NPL, the site may be restored to the NPL without the application of the Hazard Ranking System.

III. Deletion Procedures

The following procedures apply to deletion of the Site.

a. The EPA, Region 7, issued a Record of Decision (ROD) which documented the required remedial action.

b. All appropriate responses by responsible parties have been implemented as documented in the Final Close-Out Report dated August 2, 2006.

c. The state of Nebraska concurred with deletion of the Site from the NPL. The EPA consulted with the state of Nebraska on the deletion of the Site Start Printed Page 54765from the NPL prior to developing this direct final notice of deletion. Concurrently with the publication of this direct final notice of deletion, a notice of the availability of the parallel notice of intent to delete published today in the “Proposed Rules” section of the Federal Register is being published in a major local newspaper of general circulation at or near the Site and is being distributed to appropriate Federal, State, and local government officials and other interested parties; the newspaper notice announces the 30-day public comment period concerning the notice of intent to delete the Site from the NPL.

d. The EPA placed copies of documents supporting the deletion in the Deletion Docket at the Site information repositories identified above.

e. If adverse comments are received within the 30-day public comment period on this document, the EPA will publish a timely notice of withdrawal of this direct final notice of deletion before its effective date and will prepare a response to comments and continue with the deletion process on the basis of the notice of intent to delete and the comments already received.

Deletion of a site from the NPL does not itself create, alter, or revoke any individual's rights or obligations. Deletion of the site from the NPL does not in any way alter EPA's right to take enforcement actions, as appropriate. The NPL is designed primarily for informational purposes and to assist EPA management. Section 300.425(e)(3) of the NCP states that the deletion of a site from the NPL does not preclude eligibility for future response actions should future conditions warrant such actions.

IV. Basis for Intended Site Deletion

The following information provides EPA's rationale for deleting the Site from the NPL:

Site Location

The Site is located in Lancaster County in southeastern Nebraska, in and near the city of Waverly. Waverly is located along State Highway 6, approximately 10 miles north of Lincoln, Nebraska. The population of the city of Waverly is approximately 2637.

Site History

The Commodity Credit Corporation/U.S. Department of Agriculture (CCC/USDA) operated a grain storage facility in Waverly between 1952 and 1974. The facility consisted of grain storage structures (approximately 100 bins and 13 Quonset® huts) on concrete foundations. The fumigant “80/20” was used at the facility between approximately 1955 and 1965. The fumigant is reported to have been composed of 80% carbon tetrachloride and 20% carbon disulfide.

The EPA sampled the Waverly municipal water system in July 1982 as part of a nationwide survey. The analytical results indicated contamination of the public water supply (PWS) wells 1 and 3 with carbon tetrachloride and chloroform at concentrations of up to 200 micrograms per liter (μg/L) and 7.5 μg/L, respectively. Subsequent sampling of PWS 3 in 1983, 1984, 1985, and 1986 showed high levels of carbon tetrachloride and chloroform. In October 1984, the Site was placed on the NPL of sites requiring long-term remedial action.

The Site was proposed to the NPL in October 1984 and became final in June 1986. The Site contaminants posed a threat to the public health through direct contact, potential leaching from soil and the migration of contaminants in groundwater.

Immediate Actions

In May 1986, the EPA developed an Engineering Evaluation/Cost Analysis (EE/CA) Report outlining an Expedited Response Action (ERA). The ERA included pumping and treating groundwater with air stripping technology and soil gas extraction to prevent contamination of drinking water wells, prevent further plume migration, and to address soil contamination. Design of the systems was completed in May 1987.

The EPA began operation of the ERA system at the Site in February 1988. A compliance agreement between the CCC/USDA and the EPA went into effect in May 1988. In June 1988, the CCC/USDA took over the operation and maintenance of the ERA. In September 1990, the ROD was issued for the Site. The CCC/USDA is responsible for implementing the actions described in the ROD for the Site.

Record of Decision Findings

A final ROD was issued by EPA in September 1990. The remedy described in the ROD included:

  • Extraction of the contaminated groundwater using the existing groundwater extraction well (GWEX),
  • Onsite treatment of the extracted groundwater using existing air strippers,
  • Active soil extraction using existing system of soil vapor extraction wells, and
  • Continued investigation of the contaminant plume and monitoring of the system to determine the effectiveness of the remedy.

The remedial action objectives described in the ROD included:

  • The prevention of potential exposure to contaminated groundwater,
  • The protection of uncontaminated groundwater for future use by preventing further migration of the contaminated groundwater plume; and
  • The restoration of contaminated groundwater for future use as drinking water by reducing the carbon tetrachloride and chloroform concentrations below health-based criteria.

The final remedy outlined in the ROD required the following additional steps:

  • The installation of monitoring well clusters (nested wells) to the north and northwest to delineate the magnitude and extent of contamination along this potential migration route;
  • A survey of existing down-gradient wells north, northeast, and northwest of the Site;
  • Retrieval of data from the identified wells for use in citing the new monitoring well clusters;
  • A pumping and recovery aquifer test using the existing (GWEX) and monitoring wells to evaluate the hydraulic properties of the aquifer;
  • Determine the suitability of existing wells for use as extraction wells;
  • Continue sampling of the existing and new monitoring wells, water supply wells, domestic wells, vapor extraction wells, soil gas monitoring wells, air compliance points, and GWEX as specified in the performance criteria;
  • Develop a groundwater flow and transport model of sufficient detail to determine the correct pumping rate for the GWEX to enable it to capture the entire area of the plume that is above the contamination action level; and
  • Investigate potential uses for the treated water discharged from the GWEX and the air stripping system.

In 1991-1992, the CCC/USDA conducted additional site investigations at the Site to satisfy the requirements of the ROD. The principal conclusion of these site investigations were as follows:

  • Groundwater beneath the Site flows in a north-northeast direction;
  • Groundwater contamination was present only in the upper aquifer; and
  • A plume of groundwater contaminated with carbon tetrachloride and chloroform was present to the northeast of the Site.

Maximum contaminant levels detected in this northeast plume were 400 μg/L (carbon tetrachloride) and 200 μg/L (chloroform). Start Printed Page 54766

The contaminant plume to the northeast of the Site identified during CCC/USDA's 1991-1992 investigations was beyond the capture zone of the existing GWEX and is believed to have migrated from the Site before the ERA remedial system began operation. This northeast plume also needed to be captured and treated to comply fully with the ROD. To meet this objective, modifications for the remedial system were proposed by CCC/USDA in 1993 and approved by the EPA and the state of Nebraska. The modification involved installing a supplementary groundwater extraction well (SGWEX) northeast of the Site and pumping the groundwater to the Site's process building for treatment in the existing air stripper system. Additional monitoring wells were also installed to monitor the progress of the aquifer cleanup. The SGWEX system began operation in 1994.

Remedial Actions

In May 1986, the EPA developed an EE/CA Report outlining an ERA. The ERA included pumping and treating the groundwater with air stripping technology and soil gas extraction. Design of the system was completed in May 1987 and a public meeting was held in Waverly to receive comments on the proposed ERA.

The EPA began operation of the ERA system in February 1988. A compliance agreement between CCC/USDA and EPA went into effect in May 1988. In June 1988, USDA took over operation and maintenance of the ERA.

Designed for a flow rate of 169 cubic feet per minute, the vapor extraction system (VES) consisted of 17 vapor extraction wells installed in the soil above the water table at depths of 27-39 feet, with the lower 15-20 feet screened. The VES removed volatile contaminants from solution to the vapor phase as the air was drawn through the soil. The CCC discontinued operation of the VES in 1993. This action was approved by the EPA in 1995.

The air stripping system was designed to accept water at a flow rate of up to 400 gallons per minute (gpm) from the GWEX, containing concentrations of carbon tetrachloride and chloroform of up to 4,000 parts per billion (ppb) and 360 ppb, respectively, and to remove 99.9% of the contaminant concentrations. Water was pumped to a flow distributor at the top of the stripper and cascaded down through a bed of inert packing material. Clean air entered the bottom of the column and was driven upward through the packing and exited at the top of the column. The transfer of the VOCs from the water to the air produced treated water with very low VOC concentrations and air with elevated VOC levels. The air and VOCs exit the system through a stack 41 feet above grade. The treated effluent water from the air stripper is discharged to a ditch north of the Site. The effluent water flowed west via drainage ditches to Salt Creek. Effluent was monitored under a permit issued under the National Pollutant Discharge Elimination System program.

The EPA conducted a pre-final construction completion inspection at the Site in March 1994 as part of the Site close-out process. The report for the Preliminary Close-Out inspection stated that modification of the existing GWEX system to add an additional groundwater extraction well had been completed in March 1994. The Preliminary Close-Out report documented the completion of construction at the Waverly Site and provided a schedule for verification of Site cleanup and final inspection/close-out of the Site. It was completed and signed on March 29, 1994.

The GWEX was installed on the north edge of the Site in the area of greater groundwater contamination. The well was screened at 19-34 feet and 39-49 feet below the ground surface. The well was designed to have a zone of influence of 1,000 to 1,400 feet while pumping at 150 gpm. Based on sampling and monitoring results, the GWEX was shut down with EPA approval in 1995.

As part of the ROD, the EPA required the CCC/USDA to conduct an additional Site investigation program. The purpose of this investigation was to verify the downgradient performance of the ERA system and to further characterize the hydrogeologic setting. A main objective of the investigation was the installation of a nest of down-gradient monitoring wells to the northwest of the Site. These monitoring wells (6A, 6B, and 6C) were positioned on Lancaster County property. This work was completed in February 1992.

The additional Site investigations revealed a groundwater contaminant plume northeast of the Site. This plume had not been captured by the existing GWEX system since the system was only affecting the upper aquifer, and the actual radius of influence of the GWEX was approximately 800 feet. A portion of the original contaminant plume outside the influence of the GWEX was located to the northeast of the Site along 141st Street. Consequently, the remedial systems required modifications, including the installation of a SWGEX that was completed in early 1994. The Site attained the EPA status of “Construction Complete” in April 1994.

Cleanup Standards

The remedial action cleanup activities are consistent with the objectives of the NCP and will provide protection to human health and the environment. The cleanup standards for specific media are:

  • Groundwater—for carbon tetrachloride and chloroform is 5.0 μg/L and 3.8 μg/L respectively,
  • Surface water (Air Stripper Discharge)—for carbon tetrachloride and chloroform is 6.8 μg/L and 5.0 μg/L respectively,
  • Air ( Combined VOC emissions from VES air stripper system)—is 0.147 g/s,
  • Soil—for carbon tetrachloride and chloroform are 1.1 milligrams per kilograms (mg/kg) and 1.7 mg/kg respectively,
  • Soil Gas—(Combined for carbon tetrachloride and chloroform) is 6.5 μg/m3.

An Explanation of Significant Differences was issued in March 2005, deleting soil gas as a cleanup standard.

Soil and groundwater contamination—major source of contamination identified in the ROD—has been addressed. The exposure pathways considered in the risk assessment were: worker and resident exposure to soil through ingestion and direct contact, exposure to contaminated groundwater through ingestion, and exposure to air emissions generated by the air stripping and VES through inhalation. Since the likelihood of human exposure to significant levels of carbon tetrachloride and chloroform contained within soil gas at the Site was remote, this route was not considered.

The following milestones were achieved since the EPA began operation of the remedial system at the Waverly Site in February 1988:

  • Quarterly monitoring and air sampling data indicated compliance was achieved for air media and the CCC/USDA discontinued operation of the VES in 1993. This action was approved by EPA in 1995.
  • Monthly monitoring and surface water sampling data, indicated compliance levels were achieved and the air stripper system was shut down with EPA approval in 1999.
  • Quarterly monitoring and groundwater sampling results for the initial plume indicated compliance was achieved and the GWEX was shut down with EPA approval in 1995.
  • Quarterly monitoring and groundwater sampling results for the offsite plume (being addressed with the Start Printed Page 54767SGWEX) indicated compliance was achieved and in 2004 the EPA approved the shut down of the SGWEX.

Recent analytical results provided in the Third Quarter FY2006 report for the Expedited Response Action, Reporting Period April 2006 through June 2006 indicated that contaminant levels in all sampled monitoring wells were below the action levels established in the ROD.

Operation and Maintenance

The ERA systems design specifications and operation and maintenance plans are described in the February 29, 1988, report, Treatment Plant Facility Operations and Maintenance Manual for the Expedited Response Action, Waverly Groundwater Contamination Site, Waverly, Nebraska.

In November 1988, Argonne National Laboratory was contracted by the CCC/USDA to manage the Site, continue sampling, and operate/maintain the ERA systems.

The basic operation of the systems has not changed since they were first installed. However, a number of modifications and additions were made by Argonne to improve the systems' effectiveness and to facilitate operation. These changes were described in Argonne's 1991 Final Work Plan: Expedited Remedial Action, Waverly Contaminated Groundwater Site, Waverly, Nebraska.

The sampling and analysis program required monthly and quarterly sampling and analysis of groundwater for carbon tetrachloride (CCL4) and chloroform (CHCL3). Data were used to track the overall progress toward Site cleanup and to monitor potential offsite migration of contaminated groundwater. Cleanup progress was determined by comparing the measured contaminant concentrations of the environmental samples to specific target concentrations or action levels for CCL4 and CHCL3 as described in the ROD.

Since the cleanup levels described in the ROD have been achieved, routine O&M is no longer required. However, groundwater sampling at compliance points described in the ROD will continue until the final Five-Year Review is conducted in 2009.

Five-Year Review

CERCLA requires a Five-Year Review of all Sites with hazardous substances remaining above health-base levels for unrestricted use of the Site. The third Five-Year Review report was completed on September 2, 2004, pursuant to CERCLA 121(c) and to § 300.430(f)(4)(ii) of the NCP. The conclusion of this Five-Year Review assessment was that the remedial action in operation at the Site at that time was protective of human health and the environment. However, hazardous substances and pollutants remained onsite at levels above the compliance levels outlined in the ROD.

Sampling activities completed soon after the 2004 Five-Year Review was released found contamination levels in all of the compliance points described in the ROD had been achieved.

Recent analytical results provided in the Third Quarter FY2006 report for the Expedited Response Action, Reporting Period April 2006 through June 2006 indicated that contaminant levels in all sampled monitoring wells continue to be below the action levels established in the ROD. Another five-year review report is scheduled for 2009.

Community Involvement

The EPA published its Community Relations Plan in January 1986. An information repository was established at the Waverly City Hall and all of the documents used to make decisions related to the remedial action were placed there before the ROD was signed. All other reports and fact sheets were sent to the repository as they were completed. Documents in the Deletion Docket on which EPA relied for recommendation of the deletion from the NPL are available to the public in the information repositories. A public notice for this action will also be published in the local newspapers.

V. Applicable Deletion Criteria

One of the three 40 CFR 300.425(e)(1)(i) criteria for site deletion specifies that EPA may delete a Site from the NPL if, “Responsible parties or other persons have implemented all appropriate response actions required.” The EPA, with the concurrence of the state of Nebraska, has determined that all appropriate responses by the Responsible Parties have been completed and that no further response actions are necessary.

State Concurrence

In a letter dated August 24, 2006, Nebraska Department of Environmental Quality concurred with the proposed deletion of the Site from the NPL.

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List of Subjects in 40 CFR Part 300

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Dated: September 7, 2006.

William W. Rice,

Acting Regional Administrator, Region 7.

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For the reasons set out in this document,

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PART 300—[AMENDED]

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1. The authority citation for part 300 continues to read as follows:

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Authority: 33 U.S.C. 1321(c)(2); 42 U.S.C. 9601-9657; E.O. 12777, 56 FR 54757, 3 CFR, 1991 Comp., p.351; E.O. 12580, 52 FR 2923, 3 CFR, 1987 Comp., p.193.

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Appendix B—[Amended]

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2. Table 1 of Appendix B to part 300 is amended under “Nebraska” (“NE”) by removing the entry for “Waverly Groundwater Contamination.”

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[FR Doc. E6-15338 Filed 9-18-06; 8:45 am]

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